Flat heat exchanger tube

Abstract

A flat heat exchanger tube formed of a single strip of rolled aluminum, with at least one connection between the two broad sides. The connection is generally parallel to and spaced between the narrow sides and divides the heat exchanger tube into at least two chambers, and includes two legs consisting of bent opposite edges of the aluminum strip, the legs each having a head at adjacent bends along one of the broad sides and feet adjacent the other broad side. The legs lie against each other generally at their head over no more than half of the entire spacing between the two broad sides, with the legs enclosing an angle between them of about 20° to 100° or about 45° to 75°, advantageously 60°.

1. A flat heat exchanger tube formed of a single strip of rolled aluminum, said tube comprising:
 two opposite spaced apart broad sides and two opposite narrow sides; and 
 at least one connection between the two broad sides, said connection being generally parallel to and spaced between said narrow sides and dividing the heat exchanger tube into at least two chambers, and 
 including two legs consisting of bent opposite edges of the aluminum strip, said legs having first bends along one of the broad sides, second bends between the broad sides, and third bends defining feet extending from the legs adjacent the other broad side, wherein an oblique angle is defined between each leg and foot extending therefrom, wherein 
 said legs lie against each other between the first and second bends over no more than half of the entire spacing between the two broad sides, and 
 said feet define substantially flat surfaces secured to said other broad side. 
 
     
     
       2. The heat exchanger tube of  claim 1 , wherein said legs enclose an angle between them of about 20° to 100°. 
     
     
       3. The heat exchanger tube of  claim 1 , wherein said legs enclose an angle between them of about 45° to 75°. 
     
     
       4. The heat exchanger tube of  claim 3 , wherein said legs enclose an angle between them of about 60° and said legs and said other broad side substantially form an equilateral triangle. 
     
     
       5. The heat exchanger tube of  claim 3 , wherein said feet are substantially aligned and extend in opposite directions from said legs. 
     
     
       6. The heat exchanger tube of  claim 1 , wherein said legs lie against each other between the first and second bends over about ⅓ of the spacing between the two broad sides. 
     
     
       7. The heat exchanger tube of  claim 1 , wherein said feet are substantially aligned and extend in opposite directions from said legs. 
     
     
       8. The heat exchanger tube of  claim 1 , wherein the outside of the heat exchanger tube is solder-coated. 
     
     
       9. The heat exchanger tube of  claim 1 , further comprising at least one additional connection between said broad sides formed by a fold in one or the other of the broad sides, wherein the end of the fold is secured to the broad side opposite said one or the other broad side. 
     
     
       10. The heat exchanger tube of  claim 9 , wherein there are a plurality of said additional connections, said plurality of additional connections being alternately formed from said one broad side and from said other broad side. 
     
     
       11. The heat exchanger tube of  claim 1 , wherein the inner bending radius of the first bends is about 0.2 mm. 
     
     
       12. The heat exchanger tube of  claim 1 , wherein the thickness of the aluminum strip at the first bends is less than the thickness of adjacent portions of the aluminum strip. 
     
     
       13. The heat exchanger tube of  claim 12 , wherein said strip thickness at the first bends is about 40% less than the thickness of said adjacent portions of the aluminum strip. 
     
     
       14. A method of producing a flat heat exchanger tube according to  claim 1 , wherein said first bends have an inner bending radius which is rolled to a value below 0.2 mm during production of the first bends whereby the outer bending radius is minimized from the inside out by material displacement. 
     
     
       15. A flat heat exchanger tube formed of a single strip of rolled aluminum, said tube comprising:
 two opposite spaced apart broad sides and two opposite narrow sides; and 
 at least one connection between the two broad sides, said connection being generally parallel to and spaced between said narrow sides and dividing the heat exchanger tube into at least two chambers, and 
 including two legs consisting of bent opposite edges of the aluminum strip, said legs having first bends along one of the broad sides, second bends between the broad sides, and third bends defining feet extending from the legs adjacent the other broad side, 
 wherein an oblique angle is defined between each leg and foot extending therefrom; 
 wherein said legs lie against each other between the first and second bends over no more than half of the entire spacing between the two broad sides, and enclose an angle between them of about 45° to 75°. 
 
     
     
       16. The heat exchanger tube of  claim 15 , wherein said legs enclose an angle between them of about 60° and said legs and said other broad side substantially form an equilateral triangle. 
     
     
       17. The heat exchanger tube of  claim 15 , wherein said legs lie against each other between the first and second bends over about ⅓ of the spacing between the two broad sides. 
     
     
       18. The heat exchanger tube of  claim 15 , wherein the outside of the heat exchanger tube is solder-coated. 
     
     
       19. The heat exchanger tube of  claim 15 , further comprising at least one additional connection between said broad sides formed by a fold in one or the other of the broad sides, wherein the end of the fold is secured to the broad side opposite said one or the other broad side. 
     
     
       20. The heat exchanger tube of  claim 19 , wherein there are a plurality of said additional connections, said plurality of additional connections being alternately formed from said one broad side and from said other broad side. 
     
     
       21. The heat exchanger tube of  claim 15 , wherein the inner bending radius of the first bends is about 0.2 mm. 
     
     
       22. The heat exchanger tube of  claim 15 , wherein the thickness of the aluminum strip at the first bends is less than the thickness of adjacent portions of the aluminum strip. 
     
     
       23. The heat exchanger tube of  claim 22 , wherein said strip thickness at the first bends is about 40% less than the thickness of said adjacent portions of the aluminum strip. 
     
     
       24. A method of producing a flat heat exchanger tube according to  claim 15 , wherein said first bends have an inner bending radius which is rolled to a value below 0.2 mm during production of the first bends whereby the outer bending radius is minimized from the inside out by material displacement.